The present invention relates to an improved vertical shot mechanism or a die casting machine and more particularly to the mechanism for moving the shot cylinder from a position where the molten metal is introduced into the shot chamber to an injection position where the molten material is injected or shot into the die cavity.
Heretofore, various means have been provided for moving the vertical oriented cylinder shot mechanism from the molten metal receiving position to a shot injection position and vice versa. For example, reference is made to U.S. Pat. No. 4,286,648 issued on Sep. 1, 1981, in which the injection cylinder is moved from the molten metal receiving position to the injection position by the combination of a power cylinder, a link mechanism, and a cam plate which includes a guide slot. The path of the injection or shot cylinder in the U.S. Pat. No. 4,286,648 patent is guided entirely by the cam plate which results in the roller riding within the cam slot. Practical tolerances needed for such designs usually lead to unrestricted "lost" motion which results in vibrating the injection cylinder mechanism which detrimentally agitates the molten metal within the mechanism. Further, although the apparatus of said patent may possibly decrease the interval between the so called teeming of the metal and the starting of the injection as compared to prior apparatus and as alleged in the patent, it is believed that the time interval is not significantly better than prior art apparatus. Improvement in the decrease of such time interval has had a long felt need.
The apparatus of the U.S. Pat. No. 4,286,648 patent also is complicated apparatus requiring substantial column-like structures for supporting a shot cylinder mechanism and also the mechanism for actuating the same.